1.已知{an}为等差数列,a1+a3+a5=105,a2+a4+a6=99.以Sn表示{an}的前n项和,则使得Sn达到最大值的n是___.2.设Sn为等差数列{an}的前n项和,若a4=1,S5=10则当Sn取得最大值时.n的值为__.3.在等差数列{an}中.a1=25,S17=S9,
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![1.已知{an}为等差数列,a1+a3+a5=105,a2+a4+a6=99.以Sn表示{an}的前n项和,则使得Sn达到最大值的n是___.2.设Sn为等差数列{an}的前n项和,若a4=1,S5=10则当Sn取得最大值时.n的值为__.3.在等差数列{an}中.a1=25,S17=S9,](/uploads/image/z/10481871-39-1.jpg?t=1.%E5%B7%B2%E7%9F%A5%7Ban%7D%E4%B8%BA%E7%AD%89%E5%B7%AE%E6%95%B0%E5%88%97%2Ca1%2Ba3%2Ba5%3D105%2Ca2%2Ba4%2Ba6%3D99.%E4%BB%A5Sn%E8%A1%A8%E7%A4%BA%7Ban%7D%E7%9A%84%E5%89%8Dn%E9%A1%B9%E5%92%8C%2C%E5%88%99%E4%BD%BF%E5%BE%97Sn%E8%BE%BE%E5%88%B0%E6%9C%80%E5%A4%A7%E5%80%BC%E7%9A%84n%E6%98%AF___.2.%E8%AE%BESn%E4%B8%BA%E7%AD%89%E5%B7%AE%E6%95%B0%E5%88%97%7Ban%7D%E7%9A%84%E5%89%8Dn%E9%A1%B9%E5%92%8C%2C%E8%8B%A5a4%3D1%2CS5%3D10%E5%88%99%E5%BD%93Sn%E5%8F%96%E5%BE%97%E6%9C%80%E5%A4%A7%E5%80%BC%E6%97%B6.n%E7%9A%84%E5%80%BC%E4%B8%BA__.3.%E5%9C%A8%E7%AD%89%E5%B7%AE%E6%95%B0%E5%88%97%7Ban%7D%E4%B8%AD.a1%3D25%2CS17%3DS9%2C)
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